Torque wrengh or like tool



June 26, 1945. THQRNER 2,378,956

TORQUE WRENCH OR LIKE TOOL Filed June 26, 1942 'FIG.6.

' INVENTOR.

ROBERT H. THORNER ATTORNE from.

' drawing.

Patented June 26, 1945 OFFICE TORQUE WRENCH B LIKE TOOL Robert H. Thorner, Detroit, Mich.

Application'June 26, 1942, Serial No. 448,678

, Claims.

This invention relates to wrenches or like tools for turning bolts, nuts, studs, chucks, tapping and threading tools and the like with a torque not exceeding a predetermined desired torque exerted upon the element being turned. I

The principal object of my invention is to provide a simple, practical and economical wrench of the torque will change the angulartravel oi the free end of the spring before a desired extent of travel has been reached. Accordingly another object of my invention is the provision oi a cylindrical tool head having a peripheral cam slot provided'with a sharp dip (or rise), a central member projecting from one end for carrying a socket wrench or the like, and a pin projecting from the other end forengagement by the inturned end of a coiled torsion spring, the other extremity of the spring being secured in a circularly adjustable tail piece, the turning of which will change the maximum torque that can be transmitted through thespring before the dip of the cam slot, reaches a guide pin fixed in a casing surrounding the head, tail pieceand spring.

A further object of my invention is the arrangement of a Vernier-like means for making relatively fine adjustments of the maximum torque that can be transmitted by the coi1 spring before the tool head is automatically disconnected there- Other objects and advantages will be apparent to those skilled in the art upon reference to the following description and the accompanying In the drawing:

Fig. 1 is a side elevation of a torque wrench embodying'my invention.

and H respec- Fig. 8 is a bottom plan view of my torque wrench. i

.Fig. '1 is a detail perspective view of the coil spring.

Fig. 8 is a detail vertical sectional view taken substantially on the line H of Fig. 5.

Fig. 9 is a detailsection'al view similar to Fig. 8 wherein the parts are shown in diiierent positions.

Fig. 10 is a central vertical sectional view of a modified embodiment of my invention, and

Fig. 11 is a detail horizontal section taken substantially on the line lI--il of Fig. 10.

Referring now to the drawing: numeral designates a casing, herein shown as substantially cylindrical with an open upper extremity and a lower extremity closed except for a central aperture ii. A handle 22 of any desired length is carried on the central portion of the casing, and

between the handle and the closed end of the casing is provided a threaded apertured portion- 23 for the reception of a guide pin 24 having a rounded extremity 24A. within the lower portion of the casing is loosely fitted a cylindrical tool head'il formed on its periphery with a cam slot 26 provided with a dip (or rise) portion 26A, as best shown in Fig. 2,

The rounded and A of the guide pin 14 rides in the cam slot 30 during rotative movements of the tool. head 2!. A socket wrench 21, or other tool, may be detachably secured onto a central projection 10 extending from the end or the tool head. which projection is herein shown as formed with; journal portion loosely fitting in the central aperture II of the casing, and a polygonal end portion .IIA adapted to fit within a similarly shaped aperture in the socket wrench 21.

Suitable securing means, as for example, the spring-pressed ball 28 carried bythe polygonal end portion "A and projecting into an indentation in the socket wrench 21 may be provided for insuring-"maintenance oi the socket wrench in position. The opposite extremity oi the tool head carries a central guide stem 30 and a pin 3| projecting from adjacent the periphery of the tool head (note Fig. 5). The inturned end 32A of a coil spring 32 is adapted to be engaged bythe upwardly extending pin 3| during the rotation of my improved torque wrench while the opposite extremity 32B 0! the coil spring projects upwardly into a peripheral notch "A in a cylindrical tail piece It to enable adjustment of the extent of angulartravel of the coil spring 32 in the operation or the wrench. The tail piece 33 substan tially closes the open end or the casing II with its lower extremity resting upon a shoulder 20A. A central apertured guide member 33A extends downwardly from the tail piece 33 and cooperates with the guide stem 30 in positioning the tool head 25.

As best shown in Fig. 4, the tail piece 33 is provided with a relatively large number of radial passages 333, for example, an even number like Ill,

and the casing 20 is provided with an odd-numbered series of apertures 203, one less or one greater in number than the number of radial passages 33B and uniformly spaced circumferentially around the upper portion of the casing 20. This arrangement provides a Vernier-like means for adjusting the position of the extremity 32B of the coil spring.

A headed securing member 34 of slightly less diameter than the radial passages 33B is provided with an annular depression adjacent one extremity, and the length of the securing member is such that when its head is closely adjacent the casing 20, the annular depression of the securing member will overlay the central aperture in the guide member 33A of the tail piece 33 (note Figs. 2 and 4) A ball 35 is preferably arranged to be pressed into projected position centrally of all of the radial apertures 333 by a spring 36, arranged between the ball and the upper extremity of the guide stem 30 of the tool head.

By removing the securing member 34 and partially rotating the tail piece 33, the maximum torque that can be transmitted by the coil spring 32 may be varied at will, whereupon the securing member 34 is re-inserted through whatever aperture and radial passage 33B is then in alignment. A click of the spring-pressed ball 35 as it engages the annular depression in the securing member signifies when the securing member 34 is sufliciently inserted.

To enable ready adjustment of the spring 32 to transmit predetermined torques, an accurately calibrated torque scale 31 is provided. As shown in Fig. 3, such a torque scale may be arranged with circumferentially spaced graduations on the upper surface of the tail piece 33 with a cooperatcasing 20.

In operation, a tool, such as the socket wrench 21, is secured over the polygonal end portion 28A of the tool head and adjustment made for releasing the spring after a predetermined torque or angular travel of the spring has been reached. The socket wrench is then placed over the stud or other member desired to be turned and force applied through the handle 22. While the stud turns freely, very little torque is transmitted through the spring 32, but as the resistance to turning increases, the torque transmitted through the spring likewise increases by virtue of its engagement with the pin 3| projecting upwardly from the tool head. With the increasing torque the pin3l changes its relative position within the casing and the tool head turns to bring the dip portion of its cam slot adjacent the fixed guide pin 24A. when the desired amount of torque has been reached, the guide pin 24A enters the dip portion of the cam slot and the spring is automatically disengaged from the tool head. This disengagement is such that a substantial kick is felt in actual practice clearly noticeable to the workman. Then since the spring connection is broken, further rotation of the wrench handle 22 exerts no force upon the member being turned,

but instead the wrench turns freely. If, after the member has been turned until the spring reing pointer 38 fixed on the adjacent end of the leases, the workman removes the wrench and later reapplies it in an effort to further tighten the turned member, it will be found that my improved wrench will release again when the same torque is applied. When, however, the wrench is removed from such turned member and placed onto the next member to be turned, rotation of the wrench brings the pin 3| into reengagement with the inwardly projecting end 32A of the coil spring, and the wrench turns this new member until it again reaches the desired torque and effects another release of the tool head from the spring. Thus a series of bolts, studs, etc., can be set to any desired predetermined torque, without changing the adjustment of my improved torque wrench.

To insure positive disengagement of the inturned ends 32A of the coil spring from the pin 3 I preferably utilize the longitudinal movement of the tool head Within the casing to assist in such disengagement. As best shown in Figs. 8 and 9. I arrange a headed pin 39 within a shouldered opening 40 extending through the tool head, a

light spring 4| being mounted to normally press the pin 39 into engagement with the end wall of the casing 20 in all positions of said tool head. As the spring 32 is wound during the rotative movement of the tool head, said spring elongates and the cam slot is appropriately formed with a gradual rise to accommodate such elongation of the spring 32. The tool head accordingly moves longitudinally within the casing and as it approaches the lower end of the casing, the upper extremity of the pin 39 protrudes above the tool wear.

vI have found that a coil spring with its convolutions normally contacting each other, substantially as shown in Figs. 2 and 7, is particularly useful in carrying out objects of my invention. Such a spring must elongate when it is wound through rotation of the tool head, and since the outer circumference of its coil is only slightly less than that of the inner wall of the casing, the spring 32 will serve as a clutchwhen it is desired to remove turned studs, bolts, threading tools, etc. During such movements to withdraw the turned elements, the first rotation of the tool head brings the pin 3| against the opposite face of the inturned end 32A of the spring to that which it engaged while the element was being turned into position, and further movement of the tool head then tends to unwind the spring 32, and in such unwinding movements, the coils of the spring closely engage the inner wall of the casing until the casing is substantially clutched to the tool head and the entire tool serves as a unit in withdrawing the turned elements.

In Figs. 10' and 11 I have shown a modified embodiment of my invention wherein in addition to the parts hereinbefore described in connection with the embodiment illustrated in Figs. 1 to 9 similar appliance.

- in 42 is normally pressed into engagement with the inner wall of the cam slot 26 and in such inner wall I have arranged a series of circumferentially spaced apertures 43, wherein the pin 42 may enter. The inclined end of the pin 42 will permit rotation of the tool head in one direction, but hold it against movement in the opposite direction for a greater distance than the nearest radial aperture 42. Thi arrangement would be useful, for example, where there is insufficient room to permit rotation of the wrench until the spring disengages. In such case, if the handle has been swung as far as room permits, the pin 42 would look the wrench at some position applying a lesser than desired torque, while the position of the wrench on the stud i changed to permit another swinging of the wrench handle through the limited space. In other words, my improved torque wrench could be utilized after the manner of a ratchet wrench untilthe desired torque has been reached.

In Fig. I have also shown one example of how my improved torque wrench can be utilized in conjunction with an ordinary socket wrench or Instead of placing the handle 22 on the casing 20, as in the first embodiment herein described, I have formed a socketed member 44 substantially centrally of the tail piece 33 for the reception of a detachable socket wrench handle 45. By virtue of thi arrangement my improved torque wrench can be interposed between the ordinary socket wrench handle and detachable socket wrench, the handle 45 fitting into the socketed portion 44 of my improved device, and'the usual socket wrench, as 21, fitting over the polygonal portion 28A of the tool head 25. Accordingly various devices, such as studs, bolts, chucks, tapping and threading tools, etc., can be set to any desired predetermined torque through the ordinary detachable socket wrench construction with my improved devic interposed between the handle and detachable socket head.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiments to be considered in all respects as illustrativ and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim: l

1. A turning tool comprising a casing carrying a guide pin, a cylindrical tool head rotatable within the casing and formed with a cam slot cooperatingwith said guide pin to move said head lengthwise of the casing during rotation, a pin extending from one end of the tool head end portion arranged to be contacted by said pin, during a portion of arevolution of the tool head and released from /contact by the lengthwise movement of the latter due to the coaction of the cam slot andguide pin a tail piece having an aperture for the reception of the other end of said spring. and means for adjusting the relative initial positions of the tool head and tail piece cent its periphery, a spring having 'a bent end portion arranged to be contacted by said pin, during a portion of'a revolution of the tool head and released from contact by the lengthwise movement of the latter due to the coaction of the cam slot and guide pin a tail piece having an I a and tail piece, one of said members having one lengthwise of the casing during rotation, a pin extending iromone end of the tool head adjaadjacent its periphery; a spring having a bent in the casing to v ry the maximum torque that I can be transmitted through saidspring to the turning of the tool head. 1

2. A/turning tool comprising a casing carrying a guide pin, a cylindrical tool headrotatable less aperture than the other, and a detachable securing pin insertable into aligned apertures-in both members.

3 A turning tool comprising a casing carrying a guide pin, a cylindrical tool head rotatable within the casing and formed with a cam slot cooperating with said guide pin to move said head cent its periphery, a spring having a bent end portion arranged to be contacted by said pin, during a portion of a revolution of the tool head and released from contact by the lengthwise movement of the latter due to the coaction of the camslot and guide pin a tail piece having an aperture for the reception of the other end of said spring, means for adjusting the initial position of the tail piece relative to the tool head to vary the maximum torque that can be transmitted through said spring to the turning of the tool head, said adjusting means including circumferentially spaced apertures in the casing and tail piece, one of said members having one less aperture than the other, a detachable securing pin insertable into aligned apertures in both members, and resilient means positioned centrally of the tail piece for holding said securing pin when inserted through any of such aligned apertures.

4. A torque wrench comprising a casing carrying a guide pin, a cylindrical tool head rotatable within the casing and having a peripheral cam slot cooperating with said guide pin to move said head lengthwise of the casing during rotation, a pin extending from one end of the tool head adjacent its periphery, a spring having an inturned end portion arranged to be contacted by said pm, during a portion of a revolution of the tool head and released from contact by the lengthwise movement of the latter due to the coaction of the cam slot and guide pin a tail piece rotatably mounted in said casing and having an aperture for the reception of the other end of said spring, whereby circumferential movement of the tail piece will vary the angular travel of the tool head before"disengagement of said spring from said pin to proportionally vary the torque transmitted through the spring, and means for securing the tail piece in various circumferentially adjusted positions.

5. A torque wrench as recited in claim 5 where,

ina calibrated scale indicating the extent of guide pin, the inturned in said cam slot is formed with a dip portion so arranged with relation to said pin on the tool head that when said dip portion reaches the end of the spring will be disengaged from said pin.

8. A torque wrench as recited in claim 5 wherein the tail piece and easing are provided with circumierentially spaced radial apertures with one less aperture in one of said members than in the other, and a detachable securing pin insertable through any aligned apertures in the casing and tail piece to maintain Vernier-like adjustments of the tail piece.

9. A torque wrench including a casing carrying a guide pin, a cylindrical tool head rotatable within the casing having a peripheral cam slot cooper-able with said guide pin, means arranged centrally of one extremity of the tool head for carrying a socketed member, a pin extending from the other end or said tool head adjacent its periphery, a closely coiled spring having an inturned end portion arranged to be contacted by said pin, and means for securing the opposite end of said spring in various adjusted positions.

10. A torque wrench including a 0 8 8 carrying a guide pin, a cylindrical tool head rotatable within the casing having a peripheral cam slot cooperable with said guide pin, means arranged centrally of one extremity of the tool head for carrying a socketed member, a pin extending from the other end of said tool head adjacent its periphery, a closely coiled spring having an inturned end portion arranged to be contacted by said pin, and means for securing the opposite end of said spring in various adjusted ositions, said cam slot having a dip portion so arranged that when said dip portion reaches the guide pin, the inturned end of the spring will be disengaged from said pin on the tool head.

11. A torque ing a guide pin, within the casing having. a peripheral cam slot cooperable, with said guide pin, means arranged centrally of one extremity of the tool head for wrench including a casing carrycarrying a socketedmember, a pin extending {mm the other end of said tool head adjacent its periphery, a closely coiled spring having an inturned end portion arranged to be contacted by said pin, means ioraecuring the opposite end of said spring a cylindrical tooi head rotatable in various adjusted positions, said cam slot hav- I ing a'dlp portion so arran ed that when said dip portion reaches the guide pin the inturned end of the spring will be disengaged from said pin on the tool head, and means operable by movement of the tool head longitudinally of the casing for aavaeso turned end portion arranged to be contacted by said pin, means ior securing the opposite end cl 7 said spring in various adjusted positions, said cam slot having a dip portion so arranged that when said dip portion reaches the guide pinvthe inturned end of the spring will be disengaged from said pin on the tool head, and means operable by movement of the tool head longitudinally of the casing for positively disengaging said spring from said pin on the tool head, said lastmentioned means including a spring-pressed pin extending through the tool head adjacent said pin and engaging an end portion of the casing.

13. A torque wrench including a casing carry ing a guide pin, a cylindrical tool head rotatable within the casing having a peripheral cam slot cooperable with said guide pin, means arranged centrallyof one extremity of the tool head for carrying a socketed member, a pin extendin from the other'end of said tool head adjacent its periphery, a closely coiled spring having an inturned end portion arranged to be contacted by said pin, means ior securing the opposite end of said spring in various circumierentially adjusted positions, said means including a member rotatable in the'casing having an aperture for the reception of a spring end, a series of spaced radial apertures in the periphery oi said member, a. series of circumierentially spaced apertures in the casing diflering in number by one from the number of said radial apertures, and a detachable securing pin insertable into aligned apertures in said member and easing.

14. A turning tool comprising a casing carrying a guide pin, a. cylindrical tool head rotatable within the casing and formed with a cam slot cooperating with said guide pin to move said head lengthwise of the casing during rotation, a pin extending from one end oi the tool head adjacent its periphery, a spring having a bent end portion arranged to be contacted by said pin during a portion of a revolution of the tool head and released irom contact by the lengthwise movement of the latter due to the coaction of the cam slot and guide pin, and means for fixing in adjusted position the opposite end of the spring to predetermine the maximum torque that can be transmitted through said spring to the tool head.

15. A turning tool comprising a casing'carrying a guide pin, a cylindrical tool head rotatable within the casing and formed with a cam slot cooperating with said guide pin to move said head lengthwise of the casing during rotation, a pin extending from one end of the tool head adjacent positively disengaging said spring from said pin on the tool head.

12. A torque wrench including a casing carrying a guide pin, a cylindrical tool head rotatable within the casing having a peripheral cam slot cooperable with said guidepin, means arranged centrally of one extremity of the tool head for carrying a socketed member, a pin extending from the other end of said tool head adjacent its periphery, a closely coiled spring having an inits periphery, a spring having a bent end portion arranged to be contacted by said pin during a portion of a revolution of the tool head, and released from contact by the lengthwise movement of the latter due to the coaction oi the cam slot and guide pin, and means for fixing in adjusted circumferential position the opposite end of the spring tovary the maximum torque that can be transmitted through said spring to the tool head.

ROBERT E. 'rr-ronmm. 

